Yeah, it's much more than a keyword editor too - batches things really quick - like resizing, adding borders, inserting text (like a watermark), and you can create basic panoramic images, thumbnails, slideshow

It also has the ability to open almost any image file type (including raw) and will batch raw files to any other image type you select (like .tiff), though it's very slow batching out the raw files; plays video and movie files, plays sound files...
I created the Shutterstock poster using the batch function in Irfanview

in way less time that it would have taken with PS.
I've been using this for about 2 years - wonderful little program. I don't use it for photo editing (colour adjustment, etc.), though it has plugins.